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<H1>IBM Visualization Data Explorer Programmer&#39;s Reference</H1>
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<H3><A NAME="HDRDXCAH" HREF="progu097.htm#PToC_218">DXCreateArrayHandle</A></H3>
<A NAME="IDX1618"></A>
<A NAME="IDX1619"></A>
<P><STRONG>Function</STRONG>
<P>
Creates a "handle"
to allow convenient access to the items
in any Array class.
<P><STRONG>Syntax</STRONG>
<BR>
<TT><STRONG><BR>
&#35;include &lt;dx/dx.h&gt;<BR>
<P><BR>
ArrayHandle DXCreateArrayHandle(Array array)<BR>
</STRONG></TT><BR>
<P><STRONG>Functional Details</STRONG>
<P>
There are three different approaches for writing functions that
support all of the defined Array classes:
<OL>
<P><LI>Use
<TT><STRONG>
DXGetArrayClass
</STRONG></TT>
to determine the specific Array class, and then use the class-specific
functions (e.g.,
<TT><STRONG>DXGetConstantArrayData</STRONG></TT>).
The
advantage of this approach is it uses the most efficient method
to access the data stored in the Array.  The disadvantage is that
you need to write different code for each Array class.
<P><LI>Use
<TT><STRONG>
DXGetArrayData
</STRONG></TT>
on all Arrays.
The advantage here is the simplicity; the disadvantage is that
<TT><STRONG>
DXGetArrayData
</STRONG></TT>
expands compact data, greatly increasing memory use.
<P><LI>Use the Array handling routines.  The advantage is that they work
on Arrays of any class without expanding the compact data; the
disadvantage, that they are slightly less efficient for some Array
classes.
<P>
The ArrayHandle created should be deleted with
<TT><STRONG>DXFreeArrayHandle</STRONG></TT> when
the user no longer needs it.
See <A HREF="progu023.htm#HDRMEMNG">4.2 , "Memory Management"</A>.
</OL>
<P><STRONG>Return Value</STRONG>
<P>
Returns an Array Handle or returns <TT><STRONG>NULL</STRONG></TT>
and sets an error code.
<P><STRONG>See Also</STRONG>
<P>
<TT><STRONG>
<A HREF="progu149.htm#HDRDXFAH">DXFreeArrayHandle</A>,
<A HREF="progu156.htm#HDRDXGAEY">DXGetArrayEntry, DXGetArrayEntries</A>,
<A HREF="progu226.htm#HDRDXIA">DXIterateArray</A>
</STRONG></TT>
<P>
<A HREF="progu046.htm#HDRARHAND">"Array Handling"</A>.
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